Design and Implementation of an LPG Leakage Detection and Automatic Power Shutdown System

Abstract

Liquefied Petroleum Gas (LPG) is widely used as a consumer gas to satisfy many consumer needs due to its affordability and availability. However, even a 10% (v/v) solution may ignite a spark. Finding LPG leaks is challenging because they are mostly colourless and odourless at low concentrations. To address this, a low-cost, reliable electronic system has been designed to detect LPG leaks and prevent ignition sources by shutting down power to the affected area using an MQ-2 gas sensor. Analog output from the MQ-2 sensor was received and processed by the ATmega13A-PU microcontroller, which compared the reading against a predefined threshold. Once the sensor threshold is reached, the microcontroller first activates a buzzer and a high-brightness red LED to alert occupants. After a 5-second delay, a 433 MHz RF transmitter sends a wireless signal to the receiver unit, which triggers a shunt-trip breaker via a solid-state relay. This action disconnects the main electrical supply, thereby eliminating the risk of sparks. The system was calibrated and tested under varying gas concentrations and distances, confirming accurate sensitivity and reliable operation. Once the power is shut down, occupants can safely ventilate the area by opening windows and doors. The system continues to operate in a loop until gas levels return to safe conditions. This approach ensures household safety, minimizes fire hazards, and provides a cost-effective solution suitable for residential and small commercial settings. Future enhancements include integrating Internet of Things (IoT) technology for remote notifications and automated ventilation controls, further improving safety and convenience.